5... e7e6  6. f1e2 The most popular move nowadays. Interestingly, Keymer is quite used to playing this position as Black, having last played it in an important Olympiad game last year. 6... g8f6  7. e1g1  7... d5d4 It's often said that knights prefer closed positions. If we look at it from that perspective, this move makes a lot of sense, especially since it gains time by threatening the white knight. Fortunately, things in chess are more complicated than that, which is why it's so fascinating.